Abstract : This paper seeks to understand how the structure of civic relationships shapes trajectories of economic change through an examination of two well-matched Rust Belt cities: Allentown, Pennsylvania and Youngstown, Ohio. Despite sharing very similar economic histories, Allentown and Youngstown have nevertheless taken dramatically different post-industrial paths since the 1970s. The paper analyses how the intersection of economic and civic social networks shapes the strategic choice and possibilities for mobilization of key organizational actors. The analysis shows that differences in the way that civic and economic relationships intersected facilitated collective action in one location and impeded it in the other. However, in contrast to much of the literature on "social capital", the results indicate the downsides of network density, particularly in times of acute economic crisis. More important than network density is that the structure of social relationships facilitate interaction--and mobilization--across social, political and economic divisions.